Carbon nanotubes can be produced in a CVD furnace to create parallel arrays of nanotubes called “forests.” The material is grown from various catalysts deposited on substrates in an e-beam evaporation system. The substrates are placed into a furnace and heated at a typical range of 600° C. to 900° C. A hydrocarbon is then flowed over the substrates providing the carbon feedstock to grow nanotubes. An inert gas such as argon or helium is used as a carrier gas to transport the hydrocarbon to the substrates. Additional gasses such as hydrogen can be added to the system to improve nanotubes growth and properties.
Growth of the nanotube forests occurs in a typical quartz tube furnace of varying diameters from one to four inches or larger. The nanotube substrates are inserted into the furnace, and the system is sealed for gas flow. Electrical elements along the length of the tube heat up the system to a desired growth temperature. Once the system is at the desired temperature the hydrocarbon is introduced into the furnace. The hydrocarbon then heats up and dissociates on the catalyst particle, which in turn grows carbon nanotube forests. After growth of typically 10-30 minutes the system is allowed to cool, and the samples are collected.